单项选择题
A．houses B．dogs C．pets D．families
A．to help children to gain a better understanding of animal life B．to prove that the saying "a rolling stone gathers no moss" is wrong C．to introduce a particular animal to the common reader D．to discuss with professionals the laziness of animals
A．is that it can’t take instructions from other people B．is that it can avoid complications and problems C．it must pay money to the customer even if he is seriously overdrawn D．it must print the customer’s signature